Synthesis of fumed silica supported Ni catalyst for carbon dioxide conversion to methane

Abstract In this study, we report the synthesis of a fumed silica supported Ni‐based catalyst for carbon dioxide conversion to methane. Ni/fumed‐SiO 2 was prepared by loading the active agent precursor solution on the high surface area fumed SiO 2 through the wet impregnation technique. Thereafter, the resulting powder was dried and reduced under hydrogen flow at 750°C for 3 h to get the desired active agent. The CO 2 catalytic hydrogenation was performed using a flow reactor between 50 and 650°C temperature, where it showed good catalytic activity and selectivity for methane. In addition, it is found to be highly stable under reaction conditions for 16 h time on stream. Fresh and used (after the stability test) catalyst samples were characterized using different techniques, such as XRD, TEM, SEM/EDX, to investigate the structural and morphological properties, and effect of exposure to reaction conditions on the catalysts. Furthermore, the reaction mechanism was investigated using in‐situ DRIFT in the temperature range 50–450°C. The results revealed the formation of formate species at early reaction stages, followed by CO that was detected as linearly adsorbed on Ni surface, and lastly methane formation. © 2020 Society of Chemical Industry and John Wiley & Sons, Ltd.